Electron device using hollow resonator



Sept. 2, 1941. (j 2,254,796

ELECTRON DEVICE USING HOLLOW RESONATOR Filed NOV. 25, 1940 Inventor: Herbevt, D'ring,

by (5 x9 His Attorney.

Patented Sept. 2, 1941 ELECTRON DEVICE USING HOLLOW RESONATOR Herbert Diiring, Berlin-Friedenau, Germany, assignor to General Electric Company, a corporation of New York Application November 25, 1940, Serial No. 367,130 In Germany October 16, 1939 2 Claims.

The present invention relates to improvements in high frequency electronic apparatus of the type which includes means for producing a stream of electrons, means for modulating the stream, and a hollow resonator adapted to be traversed and excited by the modulated streams. It pertains particularly to that class of such apparatus which employs as a resonator a hollow body having spaced wall portions in the form of electronpermeable grids which are successively traversed by the electron stream.

It is an object of the invention to make possible easy tuning of resonators of the character above referred to as well as to permit the substitution or interchanging of different resonators without otherwise altering the arrangement of the electronic apparatus as a whole. This end is attained in accordance with one embodiment of the invention by placing the grid-portions of the hollow resonator inside the envelope which encloses the electron beam producing means and by placing the remainder of the resonator outside the envelope in a readily accessible location.

The features which I desire to protect herein are pointed out with particularity in the appended claims. The invention itself, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the drawing in which Fig. 1 illustrates diagrammatically the class of apparatus to which my invention pertains and Figs. 2 and 3 are enlarged detailed views illustrating the structural aspects of the invention. Fig. 3 is a section taken on line 33 of Fig. 2.

Referring particularly to Fig. 1 there is shown a known type of high frequency apparatus, the operation of which depends upon the effective utilization of electron transit time effects. The apparatus includes an electron emissive cathode l which is heated by means of a resistance filament 2, the filament being supplied heating current from a suitable voltage source 3. The electrons emitted by the cathode l are formed into a concentrated beam of uniform velocity by the action of a series of accelerating and focusing electrodes 4, these electrodes being maintained appropriately positive with respect to the cathode by means of batteries 3.

The electron stream thus created (indicated by the dot-dash line 5) is caused to traverse successively a pair of hollow bodies 6 and l which are rotationally symmetrical with respect to an axis of rotation represented by the path of the electron stream. Each of these bodies comprises mutually spaced wall portions (indicated at 6' and 'l') which are of grid-like character and which are arranged transversely to the path of the electrons.

For known reasons, which need not be elaborated here, small disturbances in electron velocity produced during the passage of the electron stream through the body 6 maybe made to effect relatively strong excitation of the body I as the stream traverses the latter body. This result is attributable mainly to electron-sorting effects due to the velocity changes which occur within the body 6, and it depends for its fullest realization upon a proper correlation of the spacing and dimensions of the two hollow bodies. Assuming that these factors are properly coordinated, a portion of the high frequency energy developed by resonance effects within the hollow body I may be fed back to the body 6 through an appropriate coupling connection 8 and the system thus maintained in sustained oscillation. After passage through the body 1 the electron beam may be collected by means of an anode H].

In the previous use of systems of the character described the high frequency resonators have either been enclosed within the confines of the evacuated envelope which houses the electronproducing structure (as in Fig. l) or have been made integral parts of such envelope. This arrangement has made it difficult to change the configuration of the resonators from time to time to adjust the tuning of the system and has also made it impossible to change resonators to permit operation at varying frequencies. These limitations are obviated by the present invention by placing the main structure of the resonator body outside the discharge envelope while leaving the grid-like portions associated with such bodies within the envelope.

A particular construction permitting this advantageous arrangement is shown in Fig. 2 wherein the numeral l2 designates a fragmentary section of an elongated envelope within which the elements necessary for producing an electron stream are assumed to be contained. (Only the portion of the envelope structure associated with a single resonator is shown.) In this case the envelope encloses a pair of spaced grid-like members l3 and I4 which form component parts of a hollow resonator capable of being excited by the passage of a modulated electron stream through the gap which separates the members. Outside the envelope and in a region generally coextensive with that subtended by the members I3 and 14 there is provided a hollow toroidal conductive body I5 which forms the remainder of the resonant. structure. This body is provided with mutually spaced inwardly directed lip portions 16 and I1 which are directly conductively connected with the grids l3 and M by means of lead-in connections I8 and I9 extending through the wall of the envelope I2.

In order to facilitate the assembly and replacement of the hollow body l it may be constituted of a pair of disengageable parts 15' and i5" (Fig. 3) which in use are joined, for example, by use of a bolt and nut connection 20. The electrical connection between the body l5 and the grids l3 and I4 may be facilitated by the provision of conductive elements, preferably annular rings 24 and 22 which extend outwardly from the exterior surface of the wall of the envelope in the respective planes of the grids and which frictionally engage the lips I6 and H of the resonant body when the latter is in assembled condition.

As a result of the arrangement described the resonant body, being externally accessible, may be physically deformed (for example, by the ap plication of mechanical pressure to the outside of the body) in order to adjust the tuning of the body in the desired manner. Furthermore, a. given resonant body may be readily removed and replaced by another body of different character without otherwise changing the elements of the electronic system.

While the invention has been described by reference to a particular embodiment thereof, it will be understood that numerous modifications may be made by those skilled in the art and I aim in the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electronic device including means for producing a beam of electrons, an elongated insulating envelope enclosing the beam-producing means, a pair of mutually spaced grid-like members within the envelope to be successively traversed by the beam, said members forming parts of a resonator to be excited by the beam, conductive elements projecting outwardly from the exterior surface of the envelope in the respective planes of the grid-like members and connected with said members through the wall of the envelope, and a hollow toroidal body outside the envelope and forming the remainder of the said resonator, said body having two mutually spaced, in wardly directed lip portions and consisting of disengageable parts maintaining the said lip portions respectively in conductive engagement with said outwardly projecting elements.

2. An electronic device including means for producing a beam of electrons, an elongated envelope of insulating material enclosing the beamproducing means, a pair of relatively-closelyspaced, apertured, conductive members within the envelope to be successively traversed by the beam, said members constituting parts of a resonator to be excited by the beam, and a hollow metallic body constituting the remainder of the said resonator positioned outside the envelope and symmetrically surrounding the same, said hollow body having mutually spaced inwardly directed lip portions respectively conductively connected to said apertured members through the wall of the envelope.

HERBERT DORING. 

